On a surface of a semiconductor wafer, a liquid crystal glass substrate, or the like, a fine circuit pattern is formed in a photolithography process and an etching process, and in the photolithography process, a chemical liquid supplying apparatus for applying chemical liquid such as photoresist liquid to a surface of a wafer or a glass substrate is used. As the chemical liquid supplying apparatus, for example, as disclosed in Patent Document 1, a syringe type apparatus having a piston which is accommodated in a cylinder and reciprocally movable, and a pump chamber which is expanded/contracted by reciprocal movements of the piston. At the time of expansion of this pump chamber, chemical liquid is sucked into the pump chamber from a chemical liquid supply source, and at the time of contraction of the pump chamber, the chemical liquid is discharged from the pump chamber so that the chemical liquid is applied to an object to be coated, such as a wafer, from an application nozzle provided at the tip of an discharge side passage.
And as another example, Patent Document 2 discloses a bellows type chemical liquid supplying apparatus in which a pump chamber is expanded/contracted by extension/contraction of a bellows caused by reciprocal movements of a piston. In the bellows type chemical liquid supplying apparatus, a bellows is mounted between a connection rod provided at the tip of the piston and a cylinder, and in the bellows, that is, between the bellows and the piston, incompressible indirect medium is sealed. And when the bellows is expanded by a forward movement of the piston, the pump chamber is contracted, while when the bellows is contracted by a backward movement of the piston, the pump chamber is expanded.
In any of these type apparatuses, the chemical liquid discharged from the pump chamber is discharged from an application nozzle provided at the tip of an discharge side passage, and there are a direct operated type apparatus in which the pump chamber is directly expanded/contracted by the reciprocal movements of the piston or the expansion/contraction of the bellows, and an indirect operated type apparatus in which the pump chamber is indirectly expanded/contracted via an incompressible indirect medium. The indirect operated type chemical liquid supplying apparatus has an elastically deformable partition film which divides its internal space into the pump chamber and a driving chamber, and via the incompressible indirect medium sealed in the driving chamber formed as a compartment between the piston or the bellows and the partition film, the pump chamber is expanded/contracted by the reciprocal movements of the piston or the extension/contraction of the bellows.